A test piece preparation step of preparing a test piece (50) including a welding structure in which a welding material formed of an austenitic alloy is welded to a member formed of low-alloy steel or low-carbon steel, a hydrogen supply step of supplying hydrogen to the test piece (50), and a characteristic stress acquisition step of applying a load (F) to the test piece (50) to which hydrogen was supplied and acquiring a characteristic stress showing material mechanical properties of the test piece (50) are executed.

A method for fabricating an article includes forming a billet consisting essentially of a stainless steel composition of manganese 2.00 wt. %-24.00 wt. % chromium 19.00 wt. %-30 wt. % molybdenum 0.50 wt. %-4.0 wt. % nitrogen 0.25 wt. %-1.10 wt. % carbon 1 wt. % phosphorus 0.03 wt. % sulfur 1 wt. % nickel <22 wt. % cobalt <0.10 wt. % silicon 1 wt. % niobium 0.80 wt. % oxygen 1 wt. % copper 0.25 wt. % balance iron.
The billet is annealed and cold worked to form an article. Without annealing of the article, the article is subsequently case hardened at a single case hardening temperature to form a surface layer on a top surface thereof. Articles formed with the indicated stainless steel composition with case hardened surface layers are also provided.

Surface modified substrates and related methods are provided. A substrate having a modified surface comprises a first region and a second region. The first region is located above the second region. The first region comprises an aluminum fluoride. The second region comprises an aluminum alloy. A concentration of the aluminum fluoride gradually decreases from the first region to the second region.

Surface modified substrates and related methods are provided. A substrate having a modified surface comprises a first region and a second region. The first region is located above the second region. The first region comprises an aluminum fluoride. The second region comprises an aluminum alloy. A concentration of the aluminum fluoride gradually decreases from the first region to the second region.

Methods and systems are disclosed for processing a precursor material. The method includes introducing a substrate having a precursor material deposited on a surface of the substrate into a first zone of a vacuum chamber. The precursor material comprises copper, indium, and at least one of gallium, selenium, sulfur, sodium, antimony, boron, aluminum, and silver. The method further includes, within the first zone, heating the precursor material to a target reaction temperature within a range of about 270 C. to about 490 C. The method further includes maintaining a selenium vapor in a second zone of the vacuum chamber, and after heating the precursor material to the target reaction temperature, introducing the precursor material and the substrate to the second zone of the vacuum chamber.

The present invention is directed to methods for formation of refractory carbide, nitride, and boride coatings without use of a binding agent. The present invention is directed to methods of creating refractory coatings with controlled porosity. Refractory coatings can be formed from refractory metal, metal oxide, or metal/metal oxide composite refractory coating precursor of the 9 refractory metals encompassed by groups 4-6 and periods 4-6 of the periodic table; non-metallic elements (e.g. Si & B) and their oxides (i.e. SiO.sub.2 & B.sub.2O.sub.3) are also pertinent. The conversion of the refractory coating precursor to refractory carbide, nitride or boride is achieved via carburization, nitridization, or boridization in the presence of carbon-containing (e.g. CH.sub.4), nitrogen containing (e.g. NH.sub.3), and boron-containing (e.g. B.sub.2H.sub.6) gaseous species. Any known technique of applying the refractory coating precursor can be used. The porosity of resultant refractory coatings is controlled through compositional manipulation of composite refractory coating precursors.

The present invention is directed to methods for formation of refractory carbide, nitride, and boride coatings without use of a binding agent. The present invention is directed to methods of creating refractory coatings with controlled porosity. Refractory coatings can be formed from refractory metal, metal oxide, or metal/metal oxide composite refractory coating precursor of the 9 refractory metals encompassed by groups 4-6 and periods 4-6 of the periodic table; non-metallic elements (e.g. Si & B) and their oxides (i.e. SiO.sub.2 & B.sub.2O.sub.3) are also pertinent. The conversion of the refractory coating precursor to refractory carbide, nitride or boride is achieved via carburization, nitridization, or boridization in the presence of carbon-containing (e.g. CH.sub.4), nitrogen containing (e.g. NH.sub.3), and boron-containing (e.g. B.sub.2H.sub.6) gaseous species. Any known technique of applying the refractory coating precursor can be used. The porosity of resultant refractory coatings is controlled through compositional manipulation of composite refractory coating precursors.

Disclosed are a method for adjusting the pore size of a porous metal material and the pore structure of a porous metal material. The method comprises: permeating at least one element into the surface of the pores of the material to generate a permeated layer on the surface of the pores, so that the average pore size of the porous material is reduced to within a certain range, thus obtaining a pore structure of the porous metal material having the pores distributed on the surface of the material and the permeated layer provided on the surface of the pores.

Disclosed are a method for adjusting the pore size of a porous metal material and the pore structure of a porous metal material. The method comprises: permeating at least one element into the surface of the pores of the material to generate a permeated layer on the surface of the pores, so that the average pore size of the porous material is reduced to within a certain range, thus obtaining a pore structure of the porous metal material having the pores distributed on the surface of the material and the permeated layer provided on the surface of the pores.

A method for providing a surface finish to a metal part includes both diffusion hardening a metal surface to form a diffusion-hardened layer, and oxidizing the diffusion-hardened layer to create an oxide coating thereon. The diffusion-hardened layer can be harder than an internal region of the metal part and might be ceramic, and the oxide coating can have a color that is different from the metal or ceramic, the color being unachievable only by diffusion hardening or only by oxidizing. The metal can be titanium or titanium alloy, the diffusion hardening can include carburizing or nitriding, and the oxidizing can include electrochemical oxidization. The oxide layer thickness can be controlled via the amount of voltage applied during oxidation, with the oxide coating color being a function of thickness. An enhanced hardness profile can extend to a depth of at least 20 microns below the top of the oxide coating.